Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
7S
NEW FOLD-UP LADDER
BACKGROUND OF T~E INVENTION
It is known to use various forms of collapsible
and fold up ladders for both domestic and commercial use.
A number of these prior art embodiments are very bulky
when folded and are extremely difficult to carry. In
addition several of these ladders require time-consuming
and difficult processes for disengaging the ladder after
use. Correspondingly, most of these known ladders are
troublesome to set up for use after storage.
Typical fold up ladders are disclosed in U. S.
patents 3~216,526; 3,554,318; 3,655,012; 3,730~295 and
3,811,151,
At present~ the fold up ladders known on the
market consist of sections of several treads which are
almost o the same length as that o the main strut of
the portable ladder itsel~, to which i-t backs. These
additional sections are linked by clamps to the couple
o maln struts between which the treads are placed.
These clamps secure the struts of the main and ~~~
secondary sections allowing the longitudinal extension
o~ this secondary section along the main one in the
length it allows and its securing required by means of
anchorage o~ one section in relation to the other.
Another design consists in linking both sections, main
and secondary on their ends by a hinged joint.
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Nevertheless, this other solution is less
reliable for the use of the ladder, as the securing lug-
ged nut has to exert a great pressure in the aligned
position in order to avoid the collapsing of the end of
the ladder once it has been subject to the load of the
person stepping on the additional top section, the
effect of which load is still aggravated by the
increase originated by the lever arm of the lengthen-
ing section itself. Therefore/ this model is still
less safer than the first. Nevertheless, both show
the drawbac~ of the difficulty of handling of collaps-
ible ladders~ as well as that of their weightiness
and of that of requiring too much space when not in
use, specially if they have to be carried from one
working site to another, as they usually do not fit
into small cars.
As noted above, the presently availahle ladders
have serious drawbacks when assembling for use, or dis-
engaging for storage. In addition they are relatively
~ expensive to manufacture and not always structurally
reliable when in use.
SUMMARY OF THE INVENTION
It is therefore an object of an aspect of this
invention to provide a fold-up portable ladder devoid
of the above noted disadvantages.
An object of an aspect of this invention is to
provide a fold-up and portable ladder that is compara-
tively easy and relatively inexpensive to manufacture.
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An object of an aspect of this lnvention is to
provide a ladder that is structurally sound, and
reliable for both domestic and commercial use.
An object of an aspect of this invention is to
provide a fold-up ladder that is relatively compact when
folded, is easily stored or carried, and simple to fold
down when not in use.
An object of an aspect of this invention is to
provide a lightweight ladder that can be easily
converted into stepladders of various lengths and
designs, even stepladders where the A-frames are of
different lengths.
Various aspects of the invention are as follows:
A portable folding lean to ladder comprising a
plurality of U-shaped modules comprising a rung and two
vertical portions, said modules movably connected to
each other, and when opened becoming progressively
narrower as they approach the top of said ladder, when
folded said narrower modules fitting inside of the next
wider modules, said modules except for said widest base
module comprising in their lower portions a complete
module locking means and a module hinge means, said
locking means fixing said modules in a rigid manner when
said ladder is extended and open, said locking means
integral with said modules and comprising means adapted
to movably fit into and mate with a means located in the
upper sections of said vertical portions of said
modules, and guide portions immediately adjacent said
apertures to facilitate easy entrance of said latch into
said aperture.
A portable folding lean to ladder comprising a
plurality of U-shaped modules comprising a rung and two
vertical portions, said modules movably connected to
each other, and when opened becoming progressively
narrower as they approach the top of said ladder, when
folded said narrower modules fitting inside of the next
wider modules, said modules except for said widest base
module comprising in their lower portions a complete
module locking means and a module hinge means, said
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locking means fixing said modules in a rigid manner when
said ladder is extended and open, said locking means
integral with said modules and comprising latches
adapted to movably fit into and mate with an aperture
located in the upper sections of said vertical portions
of said modulesl and tapered grooved guide portions
immediately adjacent sald apertures to facilitate easy
entrance of said latch into said aperture.
By way of added explanation, in accordance with an
aspect of this invention there is provided a novel
fold-up portable ladder which comprises a plurality of
U-shaped sections, that form both the rungs and side
rails of a ladder when assembled, each section attached
and hinged at lts lower portion to
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the next adjacent section, positioned below each of
said hinges are latches adapted to fit into and mate
with an aperture loca~ed in the vertical wall of the
said next adjacent section~ the lowest of said U-shaped
sections being the widest and the top uppermost of
said U-shaped sections being the narrowest and each
of said sections in between being progressively
narrower as they approach the top section. The latches
are spring loaded so that when aligned with and mated
into said aperture they will remain in place and
securely hold each rung in position. To disengage
each latch~ there is positioned in each horizontal
rung portion a spring and an external latch or spring
release. When the pair of latch or spring releases
are pinched together~ the latch is forced away from
said apertures and releases each U-shaped section from
the next adjacent section. The vertical arms of each
U~shaped section thus are connected to and aligned
with the next section by the use of latches located in
the horizontal base of each U-shaped section. The
latches in the horizontal base fit into the orifice
or aperture in each vertical section adjacent to it.
Each aperture has tapered grooves or slide portions
that allow the latches to slip into the aperture
easily when setting the ladder up for use. Also, the
tips of each latch portion is tapered to conform to
the configuration of each orifice or aperture slide
portion that facilitates the movement of the latch into
the aperture. The spring releases need not be
manipulated when setting up the ladder, only when the
ladder is to be folded up after use.
Any suitable material may be used in the con-
struction of the ladder, typical materials are steel7
aluminum, other metals, plastics such as polycarbonates,
polyurethanes, polyesters, polyvinyl materials, or
- other polymers. ~lso wood fiberglass7 or other synthe-
tic materials may be used. To avoid this drawback, the
subject of the present model of utility has been design-
ed, thanks to which the ladder consists of as many
different sections as treads compose it, being hinged
one to that immediately following it, upwards in
dimension, all of them being inscribed in the lowermost
tread or section of dimensions greater than all ~he
remaining components of the ladder. In this manner,
when the ladder has been folded down, the same
consists of a multiplicity of tread-sections inscribed
ones inside the others, the whole constituting an
assembly easy to taking with shouldered and passing
2~ the arm through the central orifice in the same manner
as a roll or rope is borne.
On the other hand, this design also allows it to
place the folded-down ladder inside the luggage compart-
ment of passenger cars.
To its correct understanding, a case of
practical realization is described beneath, as an example
only~ with no limitative character, of the new fold-up
ladder, enclosing one sheet of drawings on which:
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BRIEF DESCRIPTION OF DRAWINGS AND
DESCRIPTION OF THE PREFERRED EMBODIMEN~S
The preferred embodiment of this invention is
illustrated in the accompanying drawings and descrip-
tion.
Figure 1 shows diagramatically a ladder built
in accordance with the in~ention, unfolded so that
every section is aligned with respect to the foregoing
one, being fixed through the corresponding rectract-
able securing fasteners;
Figure 2 shows the same ladder~ after having
capsized its sections and folded them down completely
being carried by the user on his shoulder;
Figure 3 is a partial side view of the lock-
ing mechanism of this invention, illustrating the
latch and aperture mating section; and
Figure 4 is a partial top view of this same
locking mechanism.
The invention consists in the ladder being.
made up of a multiplicity of U-shaped modules or
sections, showing the shape of a rectangular frame
lacking of one of the smaller laterals (2), each of
which frames has its two arms hinged (3) to the two
arms of the following smaller module, for which reason,
in the folded position, every module (1) of the ladder
is inscribed inside the frame of the foregoing one,
except the larges~(lA) corresponding to one end of
the ladder and by swinging them, the modules (1)
become alternatively placed in such a position ones
to the others~ that the ends of the arms of one group
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of modules faces the ends of the arms o the other
group of modules, all them becoming placed in the
same plane, out of which they are taken at the user's
will by pulling the last smallest module llB) upwards,
so that the assembly of modules (l) advances up to a
certain limit, after which every module ~l) is swung
around itself for 180 with reference to the formers,
so that all the modules (l) become aligned to each
other, by keying elements ~4) arranged on each module
so that in the aligned position of the greater
lateral struts, the keying elements of one of the
individual frames introduce in the orifices arranged
in the lateral struts of the aligned opposite module,
the treads of the ladder therefore forming the own
bases l5) of every U-shaped module. While in Figs. l
and 2 keying elements (4) extend beyond the plane of
arms ~l), in Figs. 3 and 4 they do not. Latch (11)
in Figs. 3 and 4 are locked internally.
DESCRIPTION OF DRAWINGS AND PREFERRED EMBODIMENTS
The invention consists as earlier noted in
that the foldable portable ladders of the type made
up by a multiplicity of U-shaped sections (1) duly
linked one to the other by hinged means l3)~ inscribed
in the external one, which is the largest of said
sections and the following of smaller size in what
concerns the foregoing section and with retractable
means of fastening the frames in their extended position,
characterized by the fact that the latch (ll) securing
one section (12) with reference to its immediately
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following section ~13) is arranged in the tread-base
(5) of the U-shape of e~ery section, the head of rung
(5) which is shaped ogivally with its peak blunted or
shaped in any other form that eases the sliding of
the latch (11) that emerges out of every arm or rung
(5) of the "U" in its linking point to the base and
nearer to the end of the mentioned tubular arm of
rectangular section, a chamber (15) being shaped in
every one of the vertical edges of the inside face of
every arm (15) and at the same height to each other.
At the centre of said internal face and between two
chambers, the opening or orifice (6) of the location
for the head of the latch lll) has been envisaged,
which chambers (15) on being one section swung with
reference to the immediate other section~ the head of
the latch (11) emerging from the base (5) of the "U"
of a section (12) encounters the corresponding chamber
~15) of the adjacent section (13)~ which, in view of
the inexistence of the chamber, this acts as a ramp
on which the head of the latch (11) is forced back,
and which on becoming one section (12) aligned with
another (13) penetrates into the central location
orifice ~6). Latch (11) in Figs. 3 and 4 only extend
into orifice (6) and does not protrude through arm
section 13 or section 1 of Figs. 1 and 2. In Fig. 4
the solid line drawing show rung (5) in released
position and dotted line in locked position. Fig. 4
shows by dotted line adjacent release (16) the
direction release (16) will go when pinched together
for release. Spring 117) facilitates both holding and
releasing latch (11) from orifice 16). Dotted line adjacent
~5) show~ 15) in locked position.
Latch release 116) when pinched together will
release latch ~11) and withdraw it from orifice 16~
permitting the ladder to be folded as hinges (3) hold the
sections together for folding.
At present in prior art ladders there exists the
drawback that if one section swings around its pivot to
fold and becomes applied to the following section, in
the moment in which the section of longitudinal beam
that constitutes the folding or unfolding section comes
to a position in which it grates the longitudinal beam
of the immediate following section, the latch that
always aims to emerge totally has to be pulled back by
hand, as it is expelled by virtue of the antagonist
action of the incorporated elastic means, and which,
in the aligned position of the sections arranged
perpend~cularly or juxtaposed will make up every strut
~ o~ the unfolded ladder or the inscription of one
section inside the other when the ladder has been fold-
ed down.
To avoid the drawback of having to actuate by
hand every one of the latches of every section of the
~5 right strut as well as that o~ the left one of he
ladder~ the present model of utility has been applied
forr as it allows ! hat this retention and re-emergency
of the latch be carried out automatically without the
intervention of the hands of the user of the ladder,
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merely by the friction of the matching surfaces of the
latch and of the strut's edges.
Figures 1 and 2 illustrate an embodiment of
this invention where latch or Xeying element ~4) extends
through the vertical arms 1, lA or lB and can be seen
external of the ladder. A second embodiment is shown
in Figs. 3 and 4 where latch lll) does not extend
through the arm ~13) but merely penetrates into orifice
(6) in section (15) of arm ~13)~ and cannot be seen
beyond the outer edge of arm ~13)~ or vertical arms
1, lA or lB of Figures 1 and 2. Figure 2 clearly
shows the tapered grooves or chambers (15) that facil-
itate the entrance of latch lll) into orifice (6) of
Figs, 3 and 4.
